I. Field of the Invention
This invention relates generally to architectural curtainwall systems, and more particularly, to a novel curtainwall system incorporating a plurality of architectural panels each having both vision and spandrel areas integral thereto.
II. Description of the Presently Available Technology
Most presently available window systems for glazing the exterior walls of buildings, i.e., curtainwall systems, have separate vision and spandrel architectural panels secured adjacent to each other by vertical and horizontal mullions mounting the edifice wherein the curtainwall system is installed. Representative examples of the present technology include U.S. Pat. No. 4,302,503 issued to Mattimoe, U.S. Pat. No. 3,951,525 issued to Ballentine, U.S. Pat. No. 4,233,796 issued to Mazzoni et al.
The vision architectural panels are characterized by having luminous or visible transmittances of at least about 5% and the separate spandrel architectural panels are characterized by luminous or visible transmittances of less than about 0.5%. Spandrel panels are principally employed to conceal those portions of a building that would not be aesthetically pleasing if capable of being viewed from the exterior of the building, including floor slabs, the vertical spans between successive viewing closures, heating and air conditioning convectors, plumbing and electrical conduits, and the like. Vision panels, on the other hand, generally include a transparent substrate, usually glass, sometimes having a transparent, reflective coating applied to a major surface thereof, which serves to reflect external light and heat incident upon the major surface to which it is applicated. Spandrel areas have been formed by the use of spandrel panels which are either intrinsically opaque or are transparent substrates, usually glass, having an opaque backing or coating material applied to a major surface thereof.
PPG Industries, Inc. manufactures and sells a glass panel under their trademark SPANDRELINE.RTM.. In PPG Industries "Architectural Data Handbook", Fifth Edition, pp. 28-31, the Spandreline.RTM. panel is described as follows:
"This custom product enables the architect to use one piece of glass containing both the spandrel and vision area within the same panel. The colored spandrel area can be positioned anywhere on the panel . . . . Scattered pinholes and non-uniformity of color in the ceramic enamel will be apparent from indoors if Spandreline is used without back-up material or closure of the same size and shape as the ceramic enameled areas."
Although the SPANDRELINE.RTM. glass panel is acceptable for its intended purpose, there are curtainwall designs where it would not be suitable. More particularly, because a monolithic panel is employed, the contrast between the vision area and the spandrel area is apparent, no matter how well the vision and spandrel area coatings are "color-matched", e.g., by the techniques taught in U.S. Pat. No. 3,951,525 issued to Ballentine. The major difficulty is that since no frame member is employed to conceal or obfuscate the line of demarcation at the interface of the vision area with the spandrel area, the interruption in color uniformity between the vision area and the spandrel area is obvious to an ordinary observer, especially under outdoor lighting conditions. In a curtainwall system, these aesthetic discontinuities are magnified.
Although the present technology is generally acceptable for providing a curtainwall having generally aesthetically harmonious vision and spandrel areas comprised of separate vision and spandrel panels, it would be advantageous to provide a curtainwall having aesthetically harmonious vision and spandrel areas, comprised of architectural panels having integral vision and spandrel areas and which would eliminate the drawbacks of the presently available panels and curtainwall systems.